Disable SelectToSpeakTest.SpeakStatusTray due to flakes.

Bug: 1158879
Change-Id: Idecf29d8caff5b215637786c688ca51a3132f2e5
Tbr: dtseng@google.com
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593774Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837195}

chrome/browser/chromeos/accessibility/select_to_speak_browsertest.cc

@@ -160,7 +160,7 @@ class SelectToSpeakTestWithLanguageDetection : public SelectToSpeakTest {
   }
 };
 
-IN_PROC_BROWSER_TEST_F(SelectToSpeakTest, SpeakStatusTray) {
+IN_PROC_BROWSER_TEST_F(SelectToSpeakTest, DISABLED_SpeakStatusTray) {
   gfx::Rect tray_bounds = ash::Shell::Get()
                               ->GetPrimaryRootWindowController()
                               ->GetStatusAreaWidget()